Professional Diamond Hole Cutter: With special brazed diamond design for porcelain, glass, marble, ceramic, rock and granite, etc. High Quality Hole Drilling: Made from carbon steel with diamond blade, ideal for drilling clean and precise holes and cutting perfect circles with these tools Longer Life: Heavy-duty hole saws provide superior performance, durability is more than 8 times Tips: The electroplated diamond coating will wear off if the tool gets too hot. Never let your drill bit run dry. for hole saw Specifications: 6mm+8mm+10mm+12mm+16mm+20mm, round handle 22mm+25mm+30mm+38mm+50mm is a triangular handle Hole depth: 30mm Total length: 65mm Package contents: 6mm, 8mm, 10mm, 12mm, 16mm, 20mm, 22mm, 25mm, 30mm, 38mm, 50mm. 11pcs Diamond Drill Bit Set